This application claims the benefit of a Japanese Patent Application No. 2002-274000 filed Sep. 19, 2002, in the Japanese Patent Office, the disclosure of which is hereby incorporated by reference.
1. Field of the Invention
The present invention generally relates to data communication methods, data communication apparatuses, data communication systems and storage media, and more particularly to a data communication method, a data communication apparatus and a data communication system which are suited for application to conferencing systems, presentation systems and the like, and to a computer-readable storage medium which stores a computer program for causing a computer to make a data communication according to such a data communication method.
2. Description of the Related Art
Presently, when making a general presentation, a presenter speaks unilaterally to listeners during the presentation. The presentation is made using a projector, a large-screen display or the like in most cases. When no reference materials are distributed for the presentation, the listener can only obtain information by watching the information displayed by the projector, large-screen display or the like.
When no reference materials are distributed for the presentation, there are problems in that the listener cannot see in advance the contents of slides which will be displayed so as to familiarize himself to the contents of the presentation, the listener cannot check in advance the portions of the presentation which are particularly of interest, and the listener cannot see the contents of the slides which have already been displayed. In addition, when the question-answer time comes after the presentation ends, the questioner may forget the slide with respect to which the questioner intended to question. Moreover, the presenter may not be able to quickly display the slide which is related to the question posed by the questioner, thereby wasting valuable question-answer time due to the troublesome operation required by the presenter to locate and display the related slide.
Some of the problems described above may be eliminated by distributing print-outs of the slides as the reference materials. For example, the listener (or questioner) may check the contents of the slide which is different from the slide which is presently being displayed by the presenter. The listener (or questioner) may also check the contents of the slide he does not understand or has questions on. However, the questioner normally cannot directly specify the slide, and the presenter must display the slide in question by listening to the questions made by the questioner. However, since the presenter must select the slide in question based on verbal communication with the questioner, it usually takes time for the presenter to select the correct slide particularly when the questions of the questioner are not clearly communicated to the presenter. In addition, after the correct-slide is selected and displayed, it is even more difficult to correctly communicate the questions of the questioner to the presenter if the questioner intends to pose questions on a portion of a figure included in the slide, for example.
On the other hand, in a conference situation, materials to be used for the discussions are distributed, and one of the participants acts as the chairman of the conference. The discussions are made based on the distributed materials, but when a speaker talks on a specific page of the materials, it may be unclear to the other participants (listeners) which page is being referred to. In this case, the listener will either keep silent and pretend he understands or, the listener must ask the speaker or the other participants which page is being referred to. However, when the speaker is interrupted directly, the speaker may feel uneasy by the interruption, and the speaker may loose concentration and forget where to restart the talk. Even when the speaker is interrupted indirectly, that is, when the listener asks another participant, the speaker may also feel uneasy by the interruption, and the speaker may loose concentration and forget where to restart the talk. Moreover, the listener who is trying to find out which portion of the materials is being discussed may not be able to catch up with the talk of the speaker and become lost because the talk proceeds while the listener is trying to find out.
Therefore, the listener can hardly understand the contents of the talk if the listener does not ask and find out which page of the materials is being discussed, but the discussions will be interrupted and will not proceed smoothly if the listener asks to find out which page of the materials is being discussed, and the latter may make the speaker and the other participants feel uneasy. When the listener asks another participant, this participant's thinking will be interrupted and this participant may become unable to catch up with the talk of the speaker and become lost.
Furthermore, when the materials include tables and graphs and the speaker wishes to discuss a numerical value in the table or graph, it is very difficult to quickly and accurately communicate the speaker's intentions to all of the listeners.
When holding the conference, the participants actively speak in most cases. Hence, if the intentions of the speaker are not accurately communicated to all of the listeners (or participants), the discussion cannot proceed as desired. It may be regarded that the discussion will proceed smoothly if the page, the numerical value in the table or graph, and the like of the materials can be instantaneously and accurately communicated to all of the participants of the conference.
Recently, various conference systems and presentation systems have been proposed, which do not print out materials to be distributed for the conference or presentation, but treats the materials in the form of electronic data (digital information) which can be inspected by the participants. Basically, most of these proposed systems employ a client-server system. Generally, the client-server system includes one or a plurality of server machines for providing one or more services, and one or a plurality of client machines for receiving the services provided by the one or plurality of server machines. Usually, a large number of client machines receive the services from a small number of server machines in the client-server system.
The client-server system was designed on the basis that, virtually all of the processes are carried out by the server machine having a high performance, and the client machine having a low performance merely receives results of the processes carried out by the server machine. However, due to recent technical progresses made, the difference between the performances of the server machine and the client machine is rapidly decreasing. In addition, due to improved processing capabilities and reduced size and weight of portable computers such as lap-top personal computers, it has become popular for the participant of the conference to bring the lap-top personal computer and take notes using the lap-top personal computer.
Due to these recent changes in the environment, the problems of the conventional client-server system which distinguishes the functions of the server machine and the client machine have become more notable.
First, in the client-server type conference system, the cost of the system is extremely high in most cases due to the complexity of the system structure, and the maintenance of the server and client machines become necessary. Accordingly, in the case of the conference system having a plurality of machines connected to each other, it is more convenient to employ a peer-to-peer network structure which does not require intervention of an exclusive server machine than to employ the client-server system which has the complex system structure. The advantages of employing the peer-to-peer network structure are evident because the location of the conference will not be limited, thereby making it possible to hold the conference at a location where the connection to the exclusive server machine is impossible, as long as the network environment exists. In addition, the peer-to-peer network structure does not require the exclusive server machine which is expensive and does not require the troublesome and costly maintenance of the exclusive server machine.
In addition, in a system in which a plurality of client machines exclusively for information inspection are connected to the server machine exclusively for conference via a network, there is a case where the server machine distributes the information centrally managed thereby so that the information displayed on each client machine becomes the same, and there is a case where the client machine sends a request for a file in the server machine and inspects the file.
In the case where the information is distributed from the server machine, the client machine cannot manipulate the information, and there are problems in that user (participant) of the client machine cannot individually look back at previous information or check the next information (page). In both cases where the information is distributed from the server machine and the client machine inspects the file of the server machine, all of the participants are referring to the same information on the respective client machines, and basically, the information cannot be manipulated from the client machine. Hence, the client machine cannot take an action with respect to the information, such as adding or deleting comments with respect to the speech or data. Even if it were possible to manipulate the information from the client machine to a certain extent, this would require the client machine to first acquire the control right to manipulate the information, thereby making the operation complex and difficult for a seamless discussion to continue. In other words, in the client-server type conference system, the displayed information is always the information which is inspected by all of the participants (client machine) of the conference. Hence, it is impossible to take personal action on the client machines, such as writing personal data or information on each client machine, and exchanging data in a 1:1 communication between two client machines.
In the case of the conference which distributes the print-outs of the materials, the participants can listen to the speaker, and at the same time, take personal action such as taking personal notes, referring to a page different from the page referred to by the speaker, and confirming the materials with another participant. Because it is possible to take such a personal action, the participant can acquire and confirm the necessary information without feeling stress.
Therefore, in order to realize a smooth conferencing, the present inventors have found it is essential to realize a technique which can clearly distinguish and effectively process three kinds of information, namely, public information to be inspected by all of the participants, local information (or personal information) for personal use, and private information to be exchanged between specific participants. However, such a desirable technique has not yet been proposed.
A Japanese Laid-Open Patent Application No. 2000-236329 proposes a system which enables the operation of a terminal by each corresponding participant of the conference, and displays personally. held information on a common display unit, so as to share the information. In this proposed system, the common display unit handles the public information, and the terminal handles the local information personally held by the participant. However, there is a problem in that this proposed system requires the provision of the common display unit exclusively for sharing the information.
A Japanese Laid-Open Patent Application No. 5-207212 proposes a telewriting system which exchanges and displays data between two remote terminals. A mode is provided to additionally write with respect to a document, and another mode is provided to manipulate the document. The two modes are appropriately switched so as to smoothly exchange the information between the two remote terminals. However, this proposed system cannot distinguish the public information and the local information, and merely attempts to smoothen the exchange of the public information.
A Japanese Laid-Open Patent Application No. 6-165171 proposes a still image conference system which is provided with a local plotting mode, and distinguishes the public information and the local information. According to this proposed system, the local information, such as personal notes, is written in the local plotting mode and managed as a local file, and the local information and the public information are distinguished by taking measures so that the local information is not transmitted to another terminal.
According to the still image conference system proposed in the Japanese Laid-Open Patent Application No. 6-165171, however, the mode is distinguished at the time of the transmission, but no measures are proposed for the time of the reception, such as when receiving information from another terminal when writing the local information such as the personal notes. Moreover, the local plotting mode is prepared only with respect to the additional writing, and no measures are proposed for other actions.
Therefore, the systems proposed in the Japanese Laid-Open Patent Applications No. 2000-236329, No. 5-207212 and No. 6-165171 do not distinguish and tread the public information which is inspected by all of the participants of the conference, the local information which is personally used by the participant, and the private information which is exchanged between the specific participants. The participants of the conference basically inspect only the public information, and it is difficult to inspect the local information and the private information. As a result, the conference may be interrupted by the participant who wishes to personally look back at the materials, and the participant may lack full understanding of the proceedings because the local information cannot be personally obtained.
As described above, in order to realize a smooth conferencing, the present inventors have found it is essential to clearly distinguish and effectively process three kinds of information, namely, the public information, the local information (or personal information), and the private information, because the participant of the conference usually wishes to confirm unclear portions of the proceedings by obtaining the local information and exchange information with specific participants by obtaining the private information, in addition to inspecting the public information. Therefore, the three kinds of information are essential to holding a conference which is useful to all of the participants. However, as described above, no proposals have yet been made to clearly distinguish the three kinds of information.